Orthopaedic structures of various types and made of various materials are well known. An orthopaedic structure is used to support and surround a body part which may be injured, diseased or which requires support and the term accordingly refers to casts, therapeutic splints, braces, jackets, shoe inserts, protective sport pads, stump sockets and the like.
Generally, orthopaedic structures have been made from cloth bandage material in combination with Plaster of Paris or from Plaster of Paris alone. The structure is generally prepared by rolling a water-wetted bandage impregnated with Plaster of Paris about the body portion to be encased and allowing it to dry to rigidity (which usually takes up to one day). Making such structures is clearly messy, time-consuming and awkward and Plaster of Paris structures are well known to be heavy. Also, Plaster of Paris structures cannot be altered once made.
A more recent form of orthopaedic structure uses polymers such as a crystalline high molecular weight conjugated diolefin polymer (e.g. trans-1, 4 polyisoprene) or a polycaprolactone mixed with a filler such as titanium dioxide and/or silica. Such structures do not have the required strength characteristics for all orthopaedic uses. In addition they lack clarity.